Juliette Binoche is going back to her roots — in more ways than one. France’s Oscar-winning leading lady hit Cannes this week, lighting up the Croisette for Olivier Assayas’ “Clouds of Sils Maria” — back at the festival which first made her name nearly 30 years ago for the acclaimed “Rendez-Vous.” Juliette says, “It was a challenge to play.” Binoche plays Maria, a respected older actress asked to act again in a revival of a play that made her famous twenty years ago as an ingenue.